#! /usr/bin/env python
# -*- coding: utf-8 -*-

# Copyright (c) Huoty, All rights reserved
# Author: Huoty <sudohuoty@163.com>
# CreateTime: 2022-05-18 19:42:44

import sys,os,hashlib,time,base64

def rc4(string, op = 'encode', public_key = 'ddd', expirytime = 0):
  ckey_lenth = 4
  public_key = public_key and public_key or ''
  key = hashlib.md5(public_key).hexdigest()
  keya = hashlib.md5(key[0:16]).hexdigest()
  keyb = hashlib.md5(key[16:32]).hexdigest()
  keyc = ckey_lenth and (op == 'decode' and string[0:ckey_lenth] or hashlib.md5(str(time.time())).hexdigest()[32 - ckey_lenth:32]) or ''
  cryptkey = keya + hashlib.md5(keya + keyc).hexdigest()
  key_lenth = len(cryptkey)
  string = op == 'decode' and base64.b64decode(string[4:]) or '0000000000' + hashlib.md5(string + keyb).hexdigest()[0:16] + string
  string_lenth = len(string)

  result = ''
  box = list(range(256))
  randkey = []

  for i in xrange(255):
    randkey.append(ord(cryptkey[i % key_lenth]))

  for i in xrange(255):
    j = 0
    j = (j + box[i] + randkey[i]) % 256
    tmp = box[i]
    box[i] = box[j]
    box[j] = tmp

  for i in xrange(string_lenth):
    a = j = 0
    a = (a + 1) % 256
    j = (j + box[a]) % 256
    tmp = box[a]
    box[a] = box[j]
    box[j] = tmp
    result += chr(ord(string[i]) ^ (box[(box[a] + box[j]) % 256]))

  if op == 'decode':
    if (result[0:10] == '0000000000' or int(result[0:10]) - int(time.time()) > 0) and result[10:26] == hashlib.md5(result[26:] + keyb).hexdigest()[0:16]:
      return result[26:]
    else:
      return None
  else:
    return keyc + base64.b64encode(result)


if __name__ == "__main__":
  string = '我在这里呢，你在那里呢'
  print(string)
  str = rc4(string,'encode')
  print(str)
  rc = rc4(str,'decode')
  print(rc)
